I recommend giving your perfectionism its own name and face.
Can't picture this inner critic? Start by thinking about a mistake you've made recently. Let the voice of the oppressor berate you ("You dumb, clumsy, fat, boring…" etc.). Listen: Does that voice sound familiar? Does it belong to your wicked stepmother, your boss, your ex-spouse, an amalgam of your least-favorite movie critics? Try to summon a visual image of the tyrant. Scribble a picture of it, and do something insulting to this picture whenever your perfectionist acts up. In time, as you neutralize the destructive power inherent in this aspect of yourself, you may well lose all fear of it.
Perfectionism never delivers on its promise of perfection. It does not work.
Some psychologists use the phrase "creative hopelessness" to describe the moments when we realize that our psychological strategies are useless or counterproductive. To arrive at creative hopelessness, write down your reason for maintaining your perfectionism. It'll probably be something like this:
If I try hard enough and I'm very careful and I follow all the rules, everything will go right and everyone will love me and I'll feel good all the time.
Now ask yourself the following question, made famous by our good friend Dr. Phil: So, how's it working for you?
The most common response I get when I ask this question, whether I'm addressing myself or a client, is laughter. Releasing our doomed, anxious hope for perfection opens us to the joy available in our actual lives—especially if we move on to the next exercise.
In order not to be cowed by imperfection, you must not only accept the imperfect, but seek it.
Try this: Choose something you've always wanted to do—paint, jog, whatever. Now set out to do this thing really badly. Your inner perfectionist may erupt in violent protest. Thank her for sharing, then reward yourself for daring to do a terrible job. An even better option is the buddy system: Commit with a friend that you'll both do something really terribly, then praise each other for following through.
If you have the guts to do this, you'll find that contrary to conventional wisdom, people love you when you're openly imperfect.
"Ninety percent of staying in shape," says one of my professional-athlete clients, "is getting to the gym." I've heard high-achieving people say the same thing about pretty much every human enterprise: Successful musicians just show up, day after day, to practice their instruments. Successful businessmen show up for their customers. Successful writers show up at the blank page. Ask any of them and they'll tell you that most days, they come nowhere near perfection. What makes them winners is not instant excellence but the sheer dumb repetition of showing up.